[R] How test contrasts/coefficients of Repeated-Measures ANOVA?

Dieter Menne dieter.menne at menne-biomed.de
Sat Dec 20 20:29:56 CET 2008

Ben Meijering <b.meijering <at> student.rug.nl> writes:

> I'm doing a Repeated-Measures ANOVA, but I don't know how to test its  
> contrasts or where to find the p-values of its coefficients. I know  
> how to find the coefficient estimates of a contrast, but not how to  
> test these estimates.
> First I do something like:
> y.aov <- aov(y ~ fac1 * fac2 + Error(subj/(fac1 * fac2)), data=data)
> Then, with
> coef(y.aov)
> I get the coefficients (which are, by default, treatment contrasts?),  
> but p-values are not provided.

See model.table and se.contrast;  and consider using lme in package nlme as an
alternative which make live much easier, if it can handle your (over?)complex


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